Showing papers on "Spin-½ published in 1976"
TL;DR: In this paper, the ground state of the d-dimensional Ising model with a transverse field is proven to be equivalent to the (d+ 1) -dimensional ising model at finite temperatures.
Abstract: The partition function of a quantal spin system is expressed by that of the Ising model, on the basis of the generalized Trotter formula. Thereby the ground state of the d-dimensional Ising model with a transverse field is proven to be equivalent to the (d+ 1) -dimensional Ising model at finite temperatures. A general relationship is established between the two partition functions of a general quantal spin system and the corresponding Ising model with many-spin interactions, which yields some rigorous results on quantum systems. Some applications are given.
875 citations
350 citations
01 Jan 1976
271 citations
TL;DR: In this article, it was shown that in SU(2) quantum gauge field theory, with isospin symmetry broken spontaneously by a triplet of scalar mesons, degrees of freedom are converted into spin degrees in the field of a magnetic monopole.
Abstract: We show that in an SU(2) quantum gauge field theory, with isospin symmetry broken spontaneously by a triplet of scalar mesons, isospinor degrees of freedom are converted into spin degrees of freedom in the field of a magnetic monopole.
209 citations
TL;DR: In this article, the spin correlation in proton-proton scattering was measured at 13.2 and 13.7$ MeV using carbon analyzers of 18.6 and 29 mg/${\mathrm{cm}}^{2}, respectively, accumulating a total of 10−4$ coincidences.
Abstract: The inequality of Bell has been tested by the measurement of the spin correlation in proton-proton scattering. Measurements were made at ${E}_{p}=13.2 \mathrm{and} 13.7$ MeV using carbon analyzers of 18.6 and 29 mg/${\mathrm{cm}}^{2}$, respectively, accumulating a total of ${10}^{4}$ coincidences. The experimental analyzing power, geometric correlation coefficients, and energy spectra are compared to the result of a Monte Carlo simulation of the apparatus. The results are in good agreement with quantum mechanics and in disagreement with the inequality of Bell if the same additional assumptions are made. The conditions for comparing the results of the experiments to the inequality of Bell are discussed.
193 citations
TL;DR: In this paper, the supersymmetry transformations follow from the relativization of a pseudoclassical lagrangian describing particles with spin, and they show that supersymmetric transformations can be obtained from relativisation of a pseudo-classical Lagrangian.
182 citations
TL;DR: In this article, the statistical mechanics of unbounded n-component spin systems on the lattice were developed and the existence and uniqueness of the infinite volume free energy density for a wide class of boundary conditions were established.
Abstract: We develop the statistical mechanics of unboundedn-component spin systems on the latticeZv interacting via potentials which are superstable and strongly tempered. We prove the existence and uniqueness of the infinite volume free energy density for a wide class of boundary conditions. The uniqueness of the equilibrium state (whose existence is established in general) is then proven for one component ferromagnetic spins whose free energy is differentiable with respect to the magnetic field.
157 citations
TL;DR: In this article, the density matrix description of spin-selective radical pair reactions is described. But it does not specify the number of radical pairs to be reactivated in a given pair.
Abstract: (1976). Density matrix description of spin-selective radical pair reactions. Molecular Physics: Vol. 32, No. 5, pp. 1491-1493.
156 citations
TL;DR: In this article, a Wannier-like stationary configuration of slow electrons in the field of a residual ion is shown and solutions of the Schrodinger equation in this limited region of space are obtained and applied to the investigation of the cross section for multiple ionization near threshold.
Abstract: Many slow electrons in the field of a residual ion are shown to have Wannier-like stationary configurations. Solutions of the Schrodinger equation in this limited region of space are obtained and applied to the investigation of the cross section for multiple ionization near threshold. Numerical results are presented for double escape in several spin and angular momentum states and for triple escape in the 2S and 4S states.
122 citations
TL;DR: In this article, the probability estimates for classical systems of particles with superstable interactions were extended to continuous spin systems, where superstability is assumed to be non-trivial.
Abstract: Probability estimates for classical systems of particles with superstable interactions [1] are extended to continuous spin systems.
109 citations
TL;DR: In this article, the effect of magnetic field on spin fluctuations in weakly ferromagnetic metals is studied by using the self-consistently renormalized spin fluctuation theory.
TL;DR: In this article, the Hartree-Fock-Begoliubov cranking equations are solved for 168, 170Yb and 174Hf. The high spin anomalies are attributed to the disappearance of the neutron pair gap in 168Yb, the realignment of an i132.
TL;DR: In this paper, the spin-dynamics of anisotropic one-dimensional spin 1/2X-Y-chains in a magnetic field were discussed and the equation of motion for several spin-operators exactly.
Abstract: In this contribution we discuss the spin-dynamics of anisotropic one-dimensional spin 1/2X-Y-chains in a magnetic field. For special values of the parameters we solve the equation of motion for several spin-operators exactly. These results we use to calculate longitudinal and transverse dynamical correlation functions at temperatureT=∞, for an Ising chain in a transverse field also the first-order high-temperature correction is given.
TL;DR: In this article, a generalized phase space method for spin operators is developed, which can be used to transform a Liouville equation into an ac-number equation, and is applied to the Heisenberg model of a magnet.
Abstract: A generalized phase space method for spin operators is developed. With the use of a spin coherent state representation, mapping rules from spin operators onto ac-number space are established; simple formulas to calculate the mappedc-number functions are also derived. A product theorem, which gives a way of mapping a product of operators, is obtained in an intuitive form. This can be advantageously used to transform a Liouville equation into ac-number equation. As an illustrative example, the method is applied to the Heisenberg model of a magnet.
CERN1
TL;DR: In this article, the long-range spin and velocity independent forces of electromagnetic origin between any two systems are studied for those cases in which no forces of this type exist to order e 2.
TL;DR: An account of the recent development of NMR spin imaging is given in this paper, where the main methods of imaging are described and illustrated with examples of images of proton spin distributions in a number of biological specimens.
Abstract: An account of the recent development of NMR spin imaging is given. The basic principles of NMR necessary to understand imaging are introduced. The main methods of imaging are described and illustrated with examples of images of proton spin distributions in a number of biological specimens.
TL;DR: In this article, the authors applied the Alexander-Kaplan method to analyze the E.S.R. spectra of symmetrical three-spin systems, undergoing fast, intermediate and slow rotational diffusion in nematic liquid crystals.
Abstract: The Alexander-Kaplan method is applied to analyse the E.S.R. spectra of symmetrical three-spin systems, undergoing fast, intermediate and slow rotational diffusion in nematic liquid crystals. Particular emphasis is given to the slow-motional region. The line shapes are calculated from a spin hamiltonian, which considers Zeeman, exchange, dipolar and hyperfine interactions of the three unpaired electrons. The predictions of the theory are tested by comparison with the temperature-dependent E.S.R. spectra of trisverdazyl radicals dissolved in nematic phase V. Good agreement is found between experimental and simulated spectra. A detailed analysis provides values for the rotational correlation times and order parameters of the radicals. They are related to the viscosity and order of the pure mesophase. A comparison shows that three-spin systems are sensitive and reliable spin probes for the investigation of viscous liquid crystals.
01 Jan 1976
TL;DR: In this paper, the dynamical susceptibilities of itinerant electron ferromagnets above T C are treated by taking account of the coupling among the spin fluctuation modes to a greater extent than was made before.
Abstract: The dynamical susceptibilities of itinerant electron ferromagnets above T C are treated by taking account of the coupling among the spin fluctuation modes to a greater extent than was made before and the relatively short wave components are shown to have characteristics of spin waves which are suppressed significantly on crossing the spin fluctuation-induced Stoner excitation boundary. In the long wave limit the theory reproduces the self-consistently renormalized spin fluctuation theory of Moriya and Kawabata.
TL;DR: In this article, a set of linear equations is derived from which the values of the deformation parameters can be calculated from the Landau parameters of the spin dependent terms in the quasi-particle interaction in nuclear matter.
TL;DR: In this paper, Hartree-Fock equations for transition matrices are formulated as an extension of the ordinary theory of atomic spectra and various truncations are identified as equivalent to different forms of many-body theories.
Abstract: Hartree--Fock equations for transition matrices are formulated as an extension of the ordinary theory of atomic spectra. These equations form a hierarchy which may be subjected to various truncations. Some of the truncations are identified as equivalent to different forms of many-body theories (random- phase approximation, time-dependent Hartree--Fock, many-body perturbation theory, etc.). Thereby we connect the modern many-body treatments more explicitly with the Condon--Shortley--Racah tradition of spectra theory and provide physical interpretations of various approximations. Spin and angular variables are factored out at the outset by angular-momentum techniques. The problem then takes the form of a system of integro-differential equations for radial wave functions, which affords conceptual and computational advantages. The correlations that are characteristically studied by many-body techniques are seen to be confined to short radial distances and could accordingly be treated by R- matrix procedures.
TL;DR: In this paper, the authors extended the self-consistent renormalization theory of spin fluctuations for weakly ferro- and antiferromagnetic metals and discussed the magnetic properties of MnSi in the light of the present theory.
TL;DR: In this article, a method for generating Yamanouchi-Kotani genealogical spin eigenfunctions which requires neither storage of eigen functions for smaller numbers of electrons, nor summations of large order, nor explicit use of results from the theory of representations of the symmetric group is given.
Abstract: A method is given for generating the Yamanouchi-Kotani genealogical spin eigenfunctions which requires neither storage of eigenfunctions for smaller numbers of electrons, nor summations of large order, nor explicit use of results from the theory of representations of the symmetric group. An explicit formula is given for the coefficients of expansion in terms of spin products. (auth)